Polyphase hammers for musical instruments



y 8, 1930. R. 'M. HILL 1,769,952

POLYPHASE HAMMERS FOR MUSICAL INSTRUMENTS Filed June 17. 1927 Patented July 8, 1930 I 1 UNITED STATES PATENT OFFICE noon n. HILL, or WASHINGTON, ms'rarc'r or comman romrriusn mamas roa irosrcar. .msmumams Application filed June 17, 1927. Serial No. 199,589.

This invention relates to musical instruments of the class which generate sounds by the striking of vibrating media with hammers, picks or the like." It is particularly 5 applicable to pianos, xylophones, mirimbas,

1 '15 the individual sound producing media will receive a plurality of sharp blows in a definite timed order with respect to the other media. In this manner a rapid succession of staccato notes of pleasing effect will be produced dur- 2 ing the usual playing of the instrument, whether by manual or automatic means. The frequency of impulses impressed upon each of the media will be the same as that for all the media; but thetiming of the imulses will be different for each medium an will correspond to the position of such mediumin the musical scale of the instrument. The term frequency of impulse used in the present specification is not to be confused with thefrequency of vibration or pitch. The latter of course is different for each medium while the former is uniform for all media at any given time.

Another object is the provision of means i for varying the frequency of impulse. An-

other is the provision for varying the impulse strength for all media simultaneously. And yet another object is the provision of means for varying the strength of impulse for any selected one of the media individually with- Fig. 3 is a sectional detail of one of the solenoid hammers employed.

The drawings illustrate the invention employed in connection with a piano. The

piano is of the manually operated type but may be operated-by power if desired. Here the capital letter S refers to any one of the piano strings and the suflix used'in conjunction therewith for certain strings indicates the position ofthe string in the scale employed in the piano. For example: Sc represents the C string in the first octave; Se the. E strin in the first octave; Sc the C string in t e second octave; and so on. Where no suffix is employed it will be understood that the string falls in its illustrated position in the scale. Similarly, the letter K refers tothe piano keys, the suffix letters being used in the same way as for the strings.

Hammers H are arranged for striking" each of the strings S. These hammers will be described as electromagnetic devices since electric power is employed for their actuation but may be fluid operated devices when pneumatic power is employed. The analogy between the electrical power system and the pneumaticpower system, regarded either as a whole or with reference to individual elements, is so complete that the diagram shown in Fig. 1, while designed for the electrical system, will serve without change to illustrate a pneumatic system.

; One of the hammers H is shown in detail in Fig. 3 and consists of astriker 10 on the end of a plunger 11 controlled by a core piece 12.. The core piece 12 operates within the bore of a magnetic coil 13, being biased to a position partly out of the coil by a spring 14 and limited in its outward movement by a stop 15.. v

The coil windings are each connected at one end to one side of a switch 17 controlled by the keys K. Preferably the switch includes a carbon-pile rheostat or the like 18 of suitable resistance so that the strength of impulse may be varied according to the pressure putuponthe individual keys. The carbon-pile rheostats for all the key switches are connected to a common conductor 20. A

rheostat R and a'source of power B are inserted along the conductor 20. \Vhereas, the carbon-pile rheostats 18 are adapted to vary the strength of impulse of individual hammers, the rheostat R is adapted to vary the strength of all the hammers collectively.

The con windings for the hammer solenoids are connected at their other ends to spaced contacts 21 of an interrupter I of any suitable type. As shown, it is of the rotary type. A contact 22 carried by an arm 23 fast upon a shaft 24 connects with the contacts 21 in the order of their arrangement about a fixed disk 25. The end of conductor 20 connects with the shaft 2% by a brush or the like. There are as many contacts 21 as there are notes in the scale 01" the instrument used, or, in case of instruments such as the mandolin and guitar, there are as many contacts as there are strings on the instruments. In the embodiment illustrated, there are twelve contacts corresponding with the twelve notes of the chromatic scale of the piano. The

corresponding keys in each octave are connected to the same contacts. Only one complete chromatic scale circuit is shown in Fig. i (that for the first octave of the C key) though several additional keys and a sutiicient number of conductors for an additional octave are illustrated.

The movable member of the interrupter I, in this case the shaft 24 and arm 23, is rotated by a motor M thru a belt or similar driving connection 26. A battery B supplies the power for operating the motor and a rheostat R serves to regulate its speed. Regulation of the motor speed controls in turn the rapidity with which the contacts of the interrupter are connected to cause the hammers to strike the keys. Normally the shaft 24 may make about two revolutions per second.

Operation of the device will be clear from the preceding detailed description. The keys are played in the usual manner. During the time a key is depresesd the interrupter will close the power circuit thereof twice per second and cause a series of blows to be imparted to its corresponding string. The interval between the time one string is struck and the time the next succeeding string is struck, i. e. the phase, will correspond to the interval between the notes of the keys being held down in the scale of the instrument. The entire arrangement and operation of the device is such that a novel and particularly pleasing eilect is produced. Also, through the various controls provided the effect may be varied in certain ways to suit the taste of the operator.

While one particular embodiment of this invention has been particularly described, it will be evident that various other embodiments are possible and are contemplated by the applicant. It is therefore to be understood that the invention is not intended to be limited except by the prior art and the scope of the appended claims.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. In a musical instrument in combination, a plurality of sound producing media of diverse tone, an impulse imparting device for each medium, means for selectively conditioning one or more of said devices for actuation, means for repeatedly causing the actuation of all conditioned devicesin a definite order of succession, and means for simultaneously varying the strength of actuation of all of said devices.

2. In a musical instrument in combination, a plurality of sound producing media of diverse tone, an impulse imparting device for each medium, means for selectively conditioning one or more of said devices for actuation, means for repeatedly causing the actuation of all conditioned devices in a definite order of succession, and means for selectively varying the strength of actuation of any one of said devices.

3. In a musical instrument in combination, a plurality of sound producing media of diverse tone, an impulse imparting device for each medium, means for selectively conditioning one or more of said devices for actuation, means for repeatedly causing the actuation of all conditioned devices in a definite order of succession, means for simultaneously varying the strength of actuation of all of said devices, and means for selectively varying the strength of actuation of any one of said devices.

at. In a musical instrument in combination, a plurality of sound producing media of di verse tone, an impulse imparting device for each medium, means for selectively conditioning one or more of said devices for actuation, means for repeatedly causing the actuation of all conditioned devices in a definite order of succession and at a definite rate, and means for varying said rate of actuation.

5. In a musical instrument in combination, a plurality of sound producing media of diverse tone, impulse imparting means for each medium, a key for each medium for selectively conditioning one or more of said impulse imparting means for actuation, and means for repeatedly causing the actuation of all conditioned impulse imparting means in a definite order of succession.

6. In a musical instrument in combination, a plurality of sound producing media of diverse tone, impulse imparting means for each medium, means for selectively conditioning one or more of said impulse imparting means for actuation, and means for repeatedly causing the actuation of all conditioned impulse i nparting means in a definite order of succession.

signature.

ROGER M. HILL. 

